Figure 2. Schematic illustration of layer node-based attack and giant component of multiplex networks.

(a) Layer node 1 of Layer-1 and layer node 4 of Layer-2 are initially attacked. (b) Soon layer nodes 1,2 of Layer-1 and 3,4 and 5 of Layer-2 become failure nodes since they do not belong to the giant component of corresponding layers. (c) However, multiplex nodes 1–6 still belong to the mutually connected giant component of the multiplex networks since they connect to the largest component through at least one type of links after damage.